.app-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 5;
  font-size: 0;
  .li {
    display: inline-block;
    font-size: 14px;
    width: 25%;
    box-sizing: border-box;
    border: solid #fff;
    border-width: 1px 0 1px 1px;
    &:last-child {
      border-right-width: 1px;
    }
    .title {
      display: block;
      color: #ff0;
      background-color: rgba(80, 80, 80, .8);
      line-height: 50px;
      font-size: 16px;
      transition: 300ms all linear 0ms;
      text-align: center;
      &:hover, &.active {
        background-color: rgba(0, 0, 0, .8);
      }
    }
  }
}
